Wireless pressure ulcer alert methods and systems therefor

ABSTRACT

Pressure monitoring methods and systems for warning a patient or caregiver that soft tissue pressure has exceeded some predetermined level that over time would necessitate moving the patient to prevent or at least reduce a risk of soft tissue damage. The methods and systems entail the use of a pressure sensing unit adapted to be applied to or near a surface of the patient&#39;s body, and a sensor associated with the sensing unit to generate electrical outputs corresponding to soft tissue pressure sensed at the surface. The electrical outputs are wirelessly monitored over a preselected time period to generate a cumulative output signal based on the electrical outputs and corresponding to whether or not the soft tissue pressure has exceeded a predetermined pressure level during the preselected time period. An alarm is generated if the cumulative output signal exceeds a predetermined cumulative threshold until the soft tissue pressure drops below the predetermined pressure level.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a division patent application of co-pending U.S. patentapplication Ser. No. 16/848,323 filed Apr. 14, 2020, which a divisionpatent application of U.S. patent application Ser. No. 14/936,596 filedNov. 9, 2015, now U.S. Pat. No. 10,638,969 issued May 5, 2020, whichclaims the benefit of U.S. Provisional Application No. 62/077,393 filedNov. 10, 2014. The contents of these prior patent documents areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention generally relates to equipment and procedures foruse with health care patients. More particularly, the present inventionencompasses methods and equipment for monitoring soft tissue pressure towhich a patient may be subjected, with the intent of reducing the riskof soft tissue damage.

Pressure (decubitus) ulcers, commonly known as bedsores, present aserious problem to bedridden and wheelchair-confined patients. Prolongedpressure from a patient's body weight upon bony prominences is the mostcommon cause of pressure ulcers. Prevention of and care for apreexisting pressure ulcer typically include treatment plans thatinvolve relieving pressure on the exposed area by positioning andmaintaining the patient off susceptible areas and any preexistingpressure ulcers, and minimizing localized pressure through the use ofgel pads and similar types of products capable of absorbing and/ordistributing pressure. However, such approaches can be insufficient ifcaregivers are unaware that a patient has shifted his/her weight ontoprominences that are prone to pressure ulcers.

There are a wide variety of pressure sensors in the industrial andmedical markets, some of which have found use in monitoring pressureulcers. Notable examples include those that use air and fluiddisplacement techniques, as well as electromechanical analog devices.Many of these sensors are very portable and can be used to measurepressures at various locations of a patient at any point in time. Thereare also sheets of pressure sensors used primarily for research thatgive color-coded results from computer programs. The latter sensor typehas been particularly used by manufacturers and some healthcarefacilities to identify maximum tissue pressures under bed and wheelchairpatients' skin areas. There are also a number of pressure monitoringdevices, for example, the Oxford Pressure Monitor MKII with 12 Sensorsystem available from the Talley Group, Ltd., and the Pressure Alertsystem available from Cleveland Medical Devices, Inc.

U.S. Pat. No. 8,535,246 to Drennan et al. discloses a pressuremonitoring system for warning a patient or caregiver that soft tissuepressure has exceeded some predetermined level that over time wouldwarrant moving the patient to prevent or at least reduce a risk of softtissue damage. The system entails the use of a pressure sensing unitthat generates electrical outputs corresponding to soft tissue pressuresensed at a surface of the patient's body. In preferred embodiments, thesystem monitors the electrical outputs over a preselected time periodand generates a cumulative output signal based on the electrical outputsand corresponding to whether or not the soft tissue pressure hasexceeded a predetermined pressure level during the preselected timeperiod. The system may generate audible and/or visual warnings if thecumulative output signal exceeds a predetermined cumulative thresholduntil the soft tissue pressure drops below the predetermined pressurelevel.

Although the Drennan et al. system provides many benefits, furtherimprovements in pressure monitoring systems would be desirable.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides pressure monitoring methods and systemssuitable for providing a warning to a patient or caregiver that softtissue pressure has exceeded some predetermined level that, over asufficient period of time, would necessitate that the patient shouldmove or be moved to prevent or at least reduce the risk of soft tissuedamage. The method and system may include improved sensors, warningsystems, and/or data recording systems over existing pressure monitoringsystems.

According to one aspect of the invention, a pressure monitoring systemincludes a pressure sensing unit adapted to be applied on or near asurface of the patient's body that is susceptible to damage from softtissue pressure. The pressure sensing unit comprises at least one sensorthat generates electrical outputs corresponding to soft tissue pressuresensed by the sensor at the surface of the patient's body. The systemincludes means for wirelessly monitoring a plurality of the electricaloutputs generated by the sensor. A counter associated with themonitoring means generates a counter value that increases from aninitial value while the soft tissue pressure exceeds a predeterminedpressure level, and decreases toward the initial value while the softtissue pressure does not exceed the predetermined pressure level.According to certain preferred aspects, the counter value increases at afirst ratio relative to actual elapsed time and the counter valuedecreases at a second ratio relative to actual elapsed time, and thesecond ratio is less than the first ratio. The system also preferablyhas means for generating an alarm while the counter value exceeds apredetermined counter value.

According to another aspect of the invention, a method of monitoringpressure and reducing the risk of soft tissue damage to a patientincludes applying a pressure sensing unit to or near a surface of thepatient's body that is susceptible to damage from soft tissue pressure.The pressure sensing unit comprises a sensor that generates electricaloutputs corresponding to soft tissue pressure sensed by the sensor atthe surface of the patient's body. A plurality of the electrical outputsgenerated by the sensor is wirelessly monitored. According to certainpreferred aspects, a counter value is generated that increases from aninitial value while the soft tissue pressure exceeds a predeterminedpressure level, and decreases toward the initial value while the softtissue pressure does not exceed the predetermined pressure level. Thecounter value increases at a first ratio relative to actual elapsed timeand the counter value decreases at a second ratio relative to actualelapsed time, and the second ratio is preferably less than the firstratio. An alarm is preferably generated while the counter value exceedsa predetermined counter value.

A significant advantage of this invention is that pressure monitoringsystems and methods of this invention are adapted to provide a warningto a patient or caregiver that specifically takes into consideration theactual risk of soft tissue damage to the patient based on the softtissue pressure level, the duration the pressure has been applied, andany interruptions of the applied pressure. In particular, the system isadapted to warn the patient and/or caregiver if a sensed soft tissuepressure level exceeds a predetermined level and whose cumulative effectwould warrant if not necessitate that the patient should move or bemoved to prevent further soft tissue damage. In addition, pressuremonitoring systems wireless sensor arrangement in which multiple sensorsmay be secured to a patient without restricting movements of the patientin a bed, and would not be required to be removed prior to moving thepatient to or from a bed. Another significant aspect of the invention isthe ability to monitor pressure, generate a signal or alarm (e.g.,audible, visual, or vibration) in the event that pressure exceeds apressure threshold, particularly for a predetermined period of time, andcontinue such a signal or alarm until the cause of the excessivepressure event has been appropriately addressed by the patient or acaregiver. In some cases, an audible, visual or vibrational signal oralarm can inform the patient of the specific anatomical location thatmust be moved. Also, the system may notify the caregiver of the warningon a mobile device, in which case the caregiver may be notified even ifnot currently in the room with the patient.

Other aspects and advantages of this invention will be betterappreciated from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically represents components of a pressure monitoringsystem in accordance with an embodiment of this invention.

FIG. 2 represents sensors and a carrier of a pressure sensing unit ofFIG. 1.

FIG. 3 represents a setting in which a patient may be wirelesslymonitored with the pressure monitoring system of FIG. 1.

FIGS. 4A and 4B represent graphic user interfaces providing for theinput of patient information and alarm time, respectively, in accordancewith a nonlimiting aspect of this invention.

FIGS. 5A and 5B represent a graphic user interface displaying a statusof activated pressure sensing assemblies in accordance with anonlimiting aspect of this invention.

FIG. 6 represents a report displaying historical data pertaining to apatient based on a recording taken while the patient was wirelesslymonitored with the pressure monitoring system of FIG. 1.

FIG. 7 represents a patient in a wheelchair being wirelessly monitoredwith the system of FIG. 1.

FIG. 8 represents wireless communications between the pressuremonitoring system of FIG. 1 and remote devices.

FIG. 9 represents an outcome entry that may be completed by a caregiveror patient after the patient has been monitored with the system of FIG.1.

FIG. 10 represents an architectural schematic representation of apressure monitoring system in accordance with another embodiment of thisinvention.

FIG. 11 represents a carrier for another embodiment of a pressuresensing unit suitable for use with the systems of FIGS. 1 and 10.

FIG. 12 represents a pressure sensing unit comprising sensors assembledwith the carrier of FIG. 11.

FIG. 13 represents an exploded view of the carrier of FIG. 11.

FIG. 14 graphically represents a nonlimiting example of a method forcorrelating pressure and time to provide alarms during patientmonitoring processes that can be performed with the systems of FIGS. 1and 10.

FIG. 15 represents an embodiment of a login page displayed on a graphicuser interface suitable for use with the systems of FIGS. 1 and 11.

FIG. 16 represents an embodiment of a welcome screen displayed on thegraphic user interface of FIG. 15, including administrative, patientinformation and monitoring tabs.

FIG. 17 represents an embodiment of an administrative (“Admin”) screenaccessed through the administrative tab of the welcome screen of FIG.16.

FIG. 18 represents an embodiment of a facilities module screen accessedthrough the administrative screen of FIG. 17.

FIG. 19 represents an embodiment of a user's module screen accessedthrough the administrative screen of FIG. 17.

FIG. 20 represents an embodiment of a settings module screen accessedthrough the administrative screen of FIG. 17.

FIG. 21 represents an embodiment of a reports module screen accessedthrough the administrative screen of FIG. 17.

FIG. 22 represents an embodiment of a patient history report accessedthrough the reports module screen of FIG. 21.

FIG. 23 represents an embodiment of a patient screen accessed throughthe patient information tab of the welcome screen of FIG. 16.

FIG. 24 represents an embodiment of patient information details screenaccessed through the patient screen of FIG. 23.

FIG. 25 represents an embodiment of a PU (pressure ulcer) status screenaccessed through the patient information details screen of FIG. 24.

FIG. 26 represents an embodiment of a monitor screen accessed throughthe monitoring tab of the welcome screen of FIG. 16.

FIG. 27 represents an embodiment of automated sensor detection displayedon the monitor screen of FIG. 26.

FIG. 28 represents an embodiment of automated sensor detectionuser-configurable variables displayed on the monitor screen of FIG. 26.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a pressure monitoring system whoseprimary function is to monitor a patient that is reclined or otherwisein a position that may result in the patient's weight applying pressureto an area of the patient's body that is susceptible to pressure ulcers,such as soft tissue overlying a bony prominence. The pressure monitoringsystem further operates to correlate soft tissue pressure levels withtime to warn if an applied pressure has met certain pressure and timethresholds that, in combination, are likely to result in or exacerbate apressure ulcer. Because a soft tissue pressure level of 30 mmHg (about4000 Pa) has become universally accepted as a critical thresholdpressure level in the development of pressure ulcers, a particularlysuitable target value for the threshold pressure used by the system isbelieved to be about 30 mmHg, though more broadly threshold pressureswithin a range of about 30 and about 40 mmHg (about 4000 to about 5300Pa) are believed to be practical and acceptable, and future medicalresearch may suggest that critical pressure levels exist outside thisrange. A variety of time periods may be utilized as suitable timethresholds (for example, ten, thirty, or sixty minutes) that can beselected by a caregiver. The selected time threshold serves as a timeperiod during which the number and duration of pressure excursions abovethe threshold pressure level are used to perform an assessment. Ifwarranted, the assessment concludes with an alarm (e.g., audible,visual, vibration, etc.) that alerts caregivers and, if conscious andsufficiently alert, the patient so that the patient can be repositionedin a timely manner to avoid or at least reduce the risk of a pressureulcer. The type and level of the alarm can be selected to induce aconscious patient to move themselves in order to relieve the soft tissuepressure and stop the alarm, saving both tissue damage and the valuabletime of a caregiver. As such, the monitoring system can also be viewedas a training device for patients who are cognitively aware and capableof repositioning themselves without assistance.

A significant feature of the invention outlined above is believed to bethe correlation of pressure and time, combined with an alarm that isresponsive to this correlation in order to reduce the likelihood that apatient will remain on fragile tissue or a pre-existing ulcer longerthan is deemed to be clinically allowable. A preferred feature of thesystem is the ability to accurately detect soft tissue pressure abovethe threshold pressure level, monitor the duration over which thepressure is above this threshold, and then either sound the alarm if thepressure remains above the threshold for the preselected time period orreset the time period if the soft tissue pressure is adequately relievedbefore the preselected time period is exceeded.

In particularly preferred embodiments, the system utilizes a counterthat is initiated to generate a cumulative output whose initial value iszero (e.g., time units such as seconds or minutes), begins to increaseonce the pressure threshold is exceeded, but decreases back toward zerotime units if the soft tissue pressure drops below the threshold. Apreferred aspect of the invention is that the counter value increases ata first ratio relative to actual elapsed time, and decreases at a secondratio relative to actual elapsed time, and wherein in preferredembodiments the second ratio is less than the first ratio. For example,an increase in the counter value may occur at a first predeterminedratio of 1:1 relative to actual elapsed time, whereas a decrease in thecounter value occurs at a second predetermined ratio of less than 1:1relative to actual elapsed time, for example, at a ratio of 1:4, inother words, one counter minute for every four actual minutes that haveelapsed after the soft tissue pressure has dropped below the threshold.In this manner, the system operates to avoid soft tissue damage bytaking into consideration not only how long the soft tissue pressurepersisted above the pressure threshold, but also the elapsed timefollowing a corrective measure taken prior to the end of the preselectedtime period if the corrective measure results in the soft tissuepressure dropping below the pressure threshold. Preferably, the counterimmediately resumes and its value again increases at the firstpredetermined ratio (e.g., a 1:1 ratio to actual time) if the patientmoves to a position that resumes the excessive soft tissue pressurecondition. Suitable electrical circuitry and timers for performing thecounter function are commercially available and well within thecapabilities of those skilled in the art, and therefore will not bediscussed in any detail here.

In view of the above, it can be appreciated that optimal performance ofthe monitoring system will be achieved if the preselected time period isbased on pressure ulcer risk assessments made by appropriately trainedmedical personnel. The monitoring system may also be equipped to retainclinical information regarding recent soft tissue pressure levels anddurations, which can be useful to more fully assess a patient's historyrelating to the risk of soft tissue damage. Such historical data, whichmay further include patient clinical information and alarm events, canbe retained by the system, such as with a memory card or memory deviceof a type commonly used in consumer electronics, or through a wirelessor cable network connection to an external database. This informationcan then be downloaded to a personal computer or the like, printed andmade a part of a patient's medical record, as well as downloaded ontoelectronic media for inclusion in a patient's hard or electronic medicalrecord.

FIG. 1 is a schematic representation of one nonlimiting embodiment of apressure monitoring system 10 of the present invention. The system 10 isshown as including a converter 12, a tablet 13 (with a partial cutawayview showing internal components), and two pressure sensing units 14adapted to monitor soft tissue pressure at one or more surface regionsof a patient's body that are susceptible to damage from soft tissuepressure. At least two sensing units 14 are preferably provided to allowmultiple areas of concern to be simultaneously monitored, though it isforeseeable that a single sensing unit 14 may be sufficient under somecircumstances. The sensing units 14 are connected to the converter 12through wireless connections. The sensing units 14 may be applieddirectly to a patient's skin, integrated into a patient's clothing,and/or integrated into the bedding on which the patient lies, forexample, into a large bed pad that covers a portion of the patient'sbed. The system 10 is shown as including a power converter 20 of anysuitable type capable of delivering an appropriate power level forelectronics within the converter 12. The system 10 is also preferablycapable of operating from battery power, such as for mobile uses (e.g.,wheelchairs, bicycles, etc.) or in the event of a power outage. For thispurpose, the converter 12 may contain a backup battery or may be adaptedto run off a battery of a self-propelled wheelchair or other powereddevice.

The converter 12 is preferably configured to wirelessly connect to thetablet 13 or similarly capable device, such as a personal computer,mobile phone, or types of mobile devices that might be referred to aspersonal digital assistants (PDA). The tablet 13 may be any type oftablet computer device suitable for wirelessly connecting with andsharing data with the converter 12. The tablet 13 may use any operatingsystem, for example, Google Android® or Apple iOS®, operating a softwareapplication installed thereon configured to interface with the converter12 and interpret data provided therefrom. The tablet 13 also preferablydisplays and provides functionality suitable for an operator to interactwith the software application. The tablet 13 of FIG. 1 is represented ashaving a display 26, preferably a touchscreen as common with currenttablets in the art. With the software application installed on thetablet 13, the display 26 may provide a status of the system 10 whichcan be conveyed to an operator, and with which the operator canconfigure the operation of the converter 12, including the selection ofthe time period as discussed above. The tablet 13 is preferablyconfigured with a graphical user interface (GUI) that guides the userfrom screen to screen on the display 26 during setup of the system, suchas when entering patient information and setting warning levels andthresholds, as well as for the purpose of controlling the download ortransfer of information to or from the converter 12 (FIGS. 4A-5B). Thedisplay 26 preferably displays the preselected time period, whether thepressure being sensed by one or more of the sensing units 14 exceeds thepressure threshold, and optionally the actual pressure being sensed.According to a particularly preferred aspect of the invention, thesoftware application is also adapted to display an elapsed time progressbar 52 (FIGS. 5A and 5B) on the display 26, which displays the totalaccumulated elapsed time that any one or more of the sensing units 14has sensed a pressure exceeding the pressure threshold. The elapsed timeprogress bar 52 displayed on the display 26 also preferably ramps upwardand backward at the same rate as the counter, providing a visual signalthat alerts a caregiver as to any accumulating time condition that mayexacerbate the pressure ulcer.

A more detailed view of an embodiment of a pressure sensing unit 14 isshown in FIG. 2, and represents the unit 14 as having a sensor 30centrally located within a carrier 32, for example, fabricated from oneor more dressing materials. The carrier 32 may be formed of a foam,hydrocolloid, alginate self-adherent dressing or other suitablematerial, and is preferably sized and shaped for the particular anatomiclocation on the patient where the pressure sensing unit 14 will belocated. As such, alternative shapes may be used and preferred for thepressure sensing unit 14 and/or its carrier 32, for example, to covercurved body structures such as the heel. The pressure sensing unit 14 isdepicted in FIG. 2 as including three pressure transducers 40 located ona printed circuit board (PCB) 34. The PCB 34 and pressure transducers 40are represented as being placeable within a pocket formed in the carrier32. The sensor 30 may further comprise a battery and components (notshown) suitable for communicating with the transducers 40 and wirelesslycommunicating with the converter 12. According to a preferred aspect ofthe invention, the sensor 30 includes a replaceable battery in a holder(not shown) providing the ability to recycle the transducers 40 ratherthan discarding them.

The sensor 30 is adapted to generate electrical outputs corresponding topressure, and particularly to soft tissue pressure to which thetransducers 40 are subjected when placed on or near a patient's body. Inorder for the system 10 to provide a reliable risk assessment, a featureof the invention is the type of transducers 40 used and their accuracyat the relatively low pressures of interest. While embodiments of thepresent invention may use variable output pressure transducers,including FlexForce® load sensors available from Tekscan, Inc.,transducers comprising pressure-sensitive contacts, effectivelyoperating as binary (on-off) switches, have also been determined to bewell suited for use in the pressure monitoring system 10 of thisinvention. In embodiments of the transducers 40 utilizing a force orpressure-sensitive contact, for each occurrence in which the pressure(or equivalent force) sensed by a transducer 40 exceeds the pressurethreshold, an electrical contact will close and complete (short) anelectrical circuit therein, causing the transducer 40 to generate anidentical output level regardless of what extent the soft tissuepressure may exceed the pressure threshold. The sensor 30 produces anelectrical output signal generated by the completed electrical circuitthat can be wirelessly transmitted to the converter 12. If any one ofthe transducers 40 in the sensor 30 exceeds the pressure threshold, theelectrical output signal is preferably transmitted to the converter 12to indicate a risk of an ulcer forming.

While the pressure sensing unit 14 is represented as comprising a singlesensor 30 containing three transducers 40 that define a triangularpattern, it is within the scope of the invention for any one or more ofthe sensing units 14 of the system 10 to comprise any number of sensors30 and/or transducers 40, which may promote the reliability and accuracyof the system 10. As nonlimiting examples, two or more transducers 40may be used to define a linear pattern, three or more transducers 40 maybe used to define a triangular pattern, etc. Preferably, the sensor 30may also comprise a vibration device for alerting the patient to thesensor 30 causing an alarm and encouraging the patient to move in such away as to relieve pressure from that sensor 30. Finally, it should benoted that the components of the sensing units 14 may be constructed tobe sufficiently thin to reduce pressure on and provide greater comfortfor the patient. Such components may include multi-layer thin filmsensors, thin-film PCBs, thin-film batteries, etc.

In view of the foregoing, it should be apparent that the construction ofthe sensor 30 and transducers 40 largely determines the sensitivity andpressure threshold of the pressure sensing units 14. Though variousconfigurations are possible, in practice suitable results have beenobtained with the RK series of dome sensors commercially available fromSnaptron, Inc. A particularly suitable dome sensor is believed to bepart number RK50040, which is reported to have a maximum trip force(Fmax) of about 40 grams. In investigations leading to this invention, a40-gram trip force applied to the RK50040 dome has been correlated to aminimum pressure level of about 32.5 mmHg (about 4330 Pa).

The construction of the sensing units 14 preferably allows each sensingunit 14 to be applied and secured to a patient's body, such as to one ormore bony prominences that are susceptible to damage from soft tissuepressure. The sensing unit 14 may be located within a disposable sleevethat can be slipped over the carrier 32 to allow reuse of the sensingunit 14.

The converter 12 preferably contains circuitry (not shown) capable ofwirelessly monitoring electrical outputs generated by each pressuresensing unit 14 over whatever time period has been selected by acaregiver. The converter 12 also preferably contains circuitry (notshown) adapted to record locations, identifications, and pressure dataof the sensors 30 of the pressure sensing units 14. For example, theconverter 12 may be configured to accept Bluetooth® low energy (BTLE)data streams from the pressure sensing units 14. The converter 12 alsopreferably contains circuitry (not shown) adapted to wirelessly connectto the tablet 13 in order to transfer data collected by the converter 12from the pressure sensing units 14. For example, the converter 12 maysend a WiFi® signal to the tablet 13 to download a single stream of datainto the application software residing on the tablet 13.

The converter 12 is preferably configured to receive BTLE signals fromthe sensors 30, preferably at least up to six sensor signals, andconvert these BTLE signals into a single WiFi® signal that includes atleast the identity of each sensor and the data corresponding to eachsensor. The converter 12 transmits the WiFi® signal to the tablet 13 andthe software application on the tablet 13 processes the WiFi® signal,identifies each sensor 30 and its corresponding data, analyzes andprovides the data to the caregiver via the display 26 and GUI. Thetablet 13 may further transmit the analyzed data to other devices, suchas a nurses' station, a mobile device, or a remote database.

A nonlimiting method of using the system 10 is represented in FIG. 3. Asrepresented, the converter 12 may be located near a patient 24 with itspower converter 20 plugged into an outlet 21. The pressure sensing units14 are shown as located over one or more anatomic sites on the patient24 by a caregiver 25. The tablet 13 may be located in any positionwithin range of the wireless connection to the converter 12.

The caregiver 25 may use the touchscreen capability of the display 26 ofthe tablet 13 and its GUI to guide the caregiver 25 during aninformation input phase of the setup for the system 10, for example, toinput an identification of the patient 24, input clinical data and sitelocations of the pressure sensing units 14, and select a time thresholddesignating the amount of time in which the number and duration ofpressure excursions may be above a threshold pressure level during anassessment prior to an alarm.

FIGS. 4A and 4B are representative of an exemplary graphical userinterface for the information input phase of the system 10. Eachpressure sensing unit 14 is preferably identified in the applicationsoftware as to its individual anatomic placement. Each of the sensingunits 14 may also be physically marked on a backside of the sensing unit14 by the caregiver 25 as to its anatomic placement. As represented inFIG. 5A, individual monitor screens on the tablet 13 may show each ofthe locations of the sensing units 14 so the caregiver 25 will knowwhich location will have caused an alarm. The patient 24 may also see orhear the alarm, but preferably will also feel vibration if the sensor 30of a pressure sensing unit 14 is equipped with a vibration device.

During an initial hardware setup phase, the tablet 13 may wirelesslysend patient data, for example, by WiFi®, to the converter 12. Theconverter 12 may then record the locations and identifications of thepressure sensing units 14. As indicated in FIG. 1, the converter 12 mayinclude LED lights 16 corresponding to each sensing unit 14 thatindicate when the monitoring function of each sensing unit 14 begins(for example, three connected sensing units 14 equal three green LEDs).The LED lights 16 may also indicate if one or more of the sensing units14 has malfunctioned, for example, due to battery life. Preferably, theconverter 12 has at least two days of stored battery life and anadditional LED light 18 to warn of battery failure of the converter 12.

During operation, the pressure sensing units 14 individually sense aload applied thereto and send wireless signals to the converter 12,which then communicates the data to the tablet 13. In FIG. 5A, thesoftware application of the tablet 13 is in communication with theconverter 12 and receives a cumulative output signal generated by theconverter 12 of the counter based on the electrical outputs of eachindividual pressure sensing unit 14 over the preselected time period. Aspreviously described, the output value of the counter is cumulative inthat it takes into consideration whether the soft tissue pressure hasexceeded the preselected pressure level established by the transducers40 of the sensor 30 during the preselected time period, as well aswhether the soft tissue pressure has dropped below the predeterminedpressure level during the time period. In this example, the converter 12is wirelessly in communication with five pressure sensing units 14. Thesensors 30 of three of the units 14 are not sensing a load that exceedsa threshold of, for example, 32 mmHg, as indicated by an upwardspointing arrows and their respective empty elapsed time progress bars52. The sensors 30 of the remaining two units 14 are represented ashaving sensed a load, as indicated by downwards pointing arrows andpartially filled elapsed time progress bars 52. In addition, these twosensing units 14 are distinguished by having different colored monitorwindows as compared to the three sensing units 14 that are not sensing aload. As explained previously, if the patient 24 were to change positionand thereby load or unload individual sensors 30, the monitor screenswould be updated accordingly. In the case of removing the load from onethe pressure sensing units 14, the partially-filled elapsed timeprogress bar 52 would begin to recede over time according to theconditions set by the caregiver 25 during the information input phase,with the rate of recession corresponding to a decrease in the countervalue that occurs at a predetermined ratio relative to the actualelapsed time that the load has not been sensed or otherwise has notexceeded the preselected pressure threshold.

When the pressure level sensed by any one of the pressure sensing units14 has exceeded the preselected pressure threshold for a time periodthat exceeded the preselected time threshold, as represented by thecompletely filled progress bars 52 for two of the sensing units 14 inFIG. 5B, the corresponding monitor screen may activate an alarm. As anexample, the monitor screen may flash a red visual alarm (as representedby the darker windows in FIG. 5B) and/or an audio alarm on the tablet 13to warn the patient 24 and caregiver 25. In addition, the vibrationdevice in the individual sensing unit 14 which surpassed its timethreshold may also be activated to directly notify the patient 24 whatarea of their body to move. In the event of an alarm being activated,wireless signals may be sent to other devices or displays, for example,wall monitor screens, nursing station personal computer screens (such ascomputer 27 in FIG. 3), mobile phones, etc., in order to alert others tothe situation.

The warnings generated by the tablet 13 and any one or more individualpressure sensing units 14 preferably continue until the soft tissuepressure sensed by the sensing unit 14 drops below the predeterminedpressure level. At this time, the monitor screen elapsed time bar 52 maystart receding over time, corresponding to a decrease in the countervalue at the predetermined ratio. Preferably, the application softwarefurther displays a history light 50 or similar indicator on the tablet13, and is used as an indication of the accumulated alarm time on thecounter. In a currently preferred embodiment of the invention, when thepressure sensed by a sensing unit 14 drops below the pressure thresholdas a result of the patient being moved off the monitored pressure ulcer,the audio and visual alarms on the tablet 13 associated with thatsensing unit 14 turn off. However, the history light 50 on the tablet 13preferably remains lit to indicate to the caregiver 25 that an alarm haspreviously been activated, even if the alarm is no longer active.Preferably, the history light 50 remains lit until deactivated by thecaregiver 25.

The tablet 13 preferably records all monitoring activities by wirelesslycommunicating with a facility storage system and/or private or publiccloud-based storage systems. FIG. 6 represents an exemplary reportformat that may be accessible to the caregiver 25 or others both toprovide improved care to the patient 24 and to provide historical datafor industry or research. As represented, the recorded historical datamay include the status of each individual sensing unit 14 over apredetermined period of time. FIG. 8 represents wireless communicationsbetween the pressure monitoring system of FIG. 1 and remote devices,such as tablets, databases, and a cloud-based storage system. Asrepresented in FIG. 8 (top left), the sensors 30 of the sensing units 14may send signals to the converter 12, which then communicates with atablet 13 (two different types shown), which then may communicatefurther through a standard network system with remote devices such ascomputers, mobile phones, and databases. In addition, FIG. 8 (bottomright) represents internal details regarding the tablet 13 relating toits communication with the converter 12 and remote devices.

When the monitoring process has stopped, ended, or been paused, theapplication software may require the caregiver 25 to complete an outcomereport or survey. The outcome report may show the final status of thepatient 24 and the wound or risk skin area at the time when the sensingunits 14 are removed from the patient 24 and the monitoring process hasended. The outcome report may be recorded in the facility storagesystem, and/or private or public cloud-based server for review orresearch purposes tied to a unique identification tag but may no longerbe attached to a particular patient. According to a preferred aspect ofthe invention, the report format (FIG. 6) may include a link or virtualbutton for providing access to the outcome report. FIG. 9 represents anexemplary outcome entry format that may be accessible to the caregiver25 or others both to provide ulcer status reporting for each anatomicarea and includes pressure ulcer grade.

FIG. 10 is an architectural schematic representation of an alternativepressure monitoring system 58. For convenience, identical referencenumerals are used in FIG. 10 to denote elements that are the same orfunctionally correspond in at least some aspects to elements describedfor the system 10 of FIG. 1. The system 58 is shown as includingmultiple individual sensors 30 that may comprise one or more pressuretransducers 40 (not shown) , a pressure sensing unit 14 in whichmultiple sensors 30 may be embedded, an onsite tablet 13, an optionalonsite converter or gateway 12, an Internet cloud 62, a web application64 communicating with an interactive voice response (IVR) and ShortMessage Service (SMS) engine 65 that is connected to the cloud 62, anonline database 66, an optional smartphone 68, an optional offsitetablet 70, and an optional offsite personal computer 72. The engine 65is preferably configured to verbally communicate with users andpatients, particularly so that the latter maybe made aware of whichsensor 30 is associated with a warning so that, if possible, the patientmay then be able to take corrective action without the involvement orintervention of a caregiver. The web application 64 also communicatesthrough Application Program Interfaces (APIs) with a patient monitoringsystem 73 and a medical knowledge-based system 75, which are shown asbeing directly accessed through the web application 64 but could beweb-based and accessed via the Internet cloud 62. The sensing unit 14with multiple embedded sensors 30 broadcasts sensor data periodicallythrough BTLE signals to the optional gateway 12 (if present) and/or theonsite tablet 13. Similarly, the sensing unit 14 also periodicallybroadcasts BTLE signals representing the sensor data to the optionalgateway 12 (if present) and/or the onsite tablet 13. The optionalgateway 12 may also broadcast BTLE signals directly to the onsite tablet13.

The Internet cloud 62 is wirelessly connected to at least one of theonsite tablets 13 and the optional gateway 12 for two-way wirelesscommunication between these devices and the cloud 62. The webapplication 64 and the online database 66 are both in two-waycommunication with the cloud 62, for example, through a wiredconnection. Finally, the smart phone 68, the offsite tablet 70, and theoffsite PC 72 are also in two-way communication with the cloud 62 usingany combination of wireless or wired signals.

FIGS. 11-13 represent a particular embodiment of the pressure sensingunit 14. As represented in FIGS. 11 and 12, the sensing unit 14 of FIGS.11-13 has a round periphery, a central aperture 78 sized to accommodatea sensor 30 (e.g., one or more transducers 40 and a vibration device 33mounted on a PCB 34), and an adhesive strip 80 that releasably overliesthe aperture 78, can be peeled back to allow placement of the sensor 30in the aperture 78, and then be reapplied over the aperture 78 to securethe sensor 30 within the aperture 78. The sensing unit 14 is preferablysized and shaped for the particular anatomic location on the patientwhere the sensing unit 14 will be located. As such, alternative shapesmay be used and preferred for the sensing unit 14.

As seen in FIG. 13, the carrier 32 of the sensing unit 14 may beconstructed to comprise first (inner) and second (outer) foam layers 74and 76 embedded between inner layers 77 and interior layers 79 a-c ofadditional dressing materials, which may be formed of a foam,hydrocolloid, alginate self-adherent dressing or other suitablematerials. FIGS. 11, 12, and 13 show the inner layers 77, the innermostinterior layer 79 c, and the inner foam layer 74 as being approximatelythe same size, and the center interior layer 79 a (between the inner andouter foam layers 74 and 76), the outer foam layer 76, and the outermostinterior layer 79 b as being approximately the same size but smallerthan the inner layers 77, the innermost interior layer 79 c, and theinner foam layer 74. At least one additional layer 81 overlies and islarger than all of the layers 74, 76, 77, and 79 a-c. The aperture 78seen in FIGS. 11 and 12 can be seen in FIG. 13 as being defined by aseries of openings 78 a formed within certain layers of the sensing unit14 that are approximately equally sized to accommodate the sensor 30,including its transducers 40 and PCB 34. The openings 78 a are formed inthe inner and outer foam layers 74 and 76 and at least the outermostinterior layer 79 b and the center interior layer 79 a between the innerand outer foam layers 74 and 76. The openings 78 a may also be definedin the innermost interior layer 79 c of dressing material so that thesensor 30 can be placed in closer proximity to the patient's skin. Inthe case of open wounds, the openings 78 a are preferably not present inthe inner layers 77 of dressing materials so that dressing material ispresent between the sensor 30 and an open wound. The lowermost layer ofthe inner layers 77 of the dressing material directly facing thepatient's skin is preferably a non-adhesive foam or absorbent materialwithout an opening 78 a formed therein. In addition, the skin-sidesurface of the lowermost inner layer 77 of dressing material directlyfacing the patient's skin may include an adhesive covering along anarrow border thereof to adhere the sensing unit 14 to the skin.

The systems 10 and 58 are not limited to the use of pressure sensingunits 14 of the types shown in FIGS. 2 and 11-13. In particular, thesystems 10 and 58 may include handheld probes integrating multiplesensing and data analysis capabilities relying on a variety of sensorsincluding thermal, RBG, 3D, chemical, hyper spectral, and situationalawareness sensors.

FIG. 14 schematically represents an example of the activity of a counterduring a patient monitoring process including a series of events thatcorrespond with a series of program responses. As with the system 10 ofFIG. 1, the system 58 of FIG. 10 preferably utilizes a separate counterassociated with each pressure sensing unit 14, and whose value increasesonce the soft tissue pressure detected by the associated pressuresensing unit 14 exceeds a predetermined pressure threshold, butdecreases while the soft tissue pressure is below the threshold. Inaddition, the counter value may increase and decrease at differentrates, for example, increase at a ratio relative to actual elapsed time(e.g., a ratio of 1:1 relative to actual elapsed time) that is higherthan the ratio at which the counter decreases relative to actual elapsedtime (e.g., a ratio of less than 1:1 relative to actual elapsed time).The counter value can be calculated by any suitable microcontrol,program, etc., and the increments at which the counter value iscalculated can be intervals of minutes, seconds, or fraction thereof. Inalternative embodiments of the systems 10 and 58, the rate at which thecounter value increases or decreases compared to elapsed time may bemodified on the basis of different variables, including but not limitedto variable pressure data obtained with the use of a variable outputpressure transducers (instead of on-off switch-type transducers),elapsed time during an alarm event, the particular body part causing thealarm condition, alarm history, historical sensor data, and/or datarelating to the patient, e.g., patient characteristics such as age,gender, health/medical condition, etc. Yet another alternative is forthe counter value to simply reset to zero after a predefined number ofminutes of elapsed time at a sensed pressure below the threshold. Suchalternatives may be particularly of interest as the understanding ofpressure ulcers evolves. Given that pressure ulcers are impacted by theamount of pressure applied over a period of time, the use of variableoutput pressure transducers may be preferred to implement an algorithmcapable of computing a counter decrease ratio that addresses the effectsof different levels of pressure over different levels of time, includingpeak, trough, average, and median pressures in relation to time, thespecific part of the body subjected to that pressure, and patient data.For example, if a body region of a patient is subjected to a pressure of32 mmHg over a period of 60 minutes, 240 minutes (corresponding to acounter decrease ratio of 1:4) may be an adequate duration of time torecover after the pressure has been relieved, whereas the same bodyregion subjected to a pressure of 75 mmHg for 60 minutes may require alonger recovery duration, for example, 300 minutes (corresponding to acounter decrease ratio of 1:5).

As a nonlimiting example, on the basis of a counter increase ratio of1:1 and a counter decrease ratio of 1:4, calculating the counter valuemay be as follows:

Current Counter Value=(Initial Counter Value)+(Time at PressureExceeding Pressure Threshold)−(Time at Pressure Below PressureThreshold)/4

According to this formula, the counter value in FIG. 14 increases froman initial value of zero at a rate of 1:1 relative to actual elapsedtime for a period of twenty minutes while the soft tissue pressuresensed by the associated pressure sensing unit 14 exceeds apredetermined pressure level, in this example, a threshold of 32 mmHg.FIG. 14 represents that the system 10/58 has been programmed to includean alarm threshold, whereby an alarm (e.g., audible, vibrational, etc.)is activated once the pressure threshold has been exceeded for tenminutes, i.e., the counter value is ten. When the sensed pressure dropsbelow the threshold at twenty minutes, the counter value is at 20 butbegins to decrease at a rate of 1:4 relative to actual elapsed time. InFIG. 14, the pressure sensed by the associated pressure sensing unit 14remains below the threshold of 32 mmHg for 120 minutes, and after eightyminutes of actual elapsed time below the pressure threshold the counterhas decreased by twenty (80/4) to return to a value of zero. The countervalue remains at zero until 120 minutes, at which time FIG. 14 indicatesthat the pressure sensed by the associated pressure sensing unit 14 hasagain exceeded the threshold and the counter value begins to increasefrom zero at the 1:1 rate relative to actual elapsed time. As indicatedin FIG. 14, the alarm is deactivated (turned off) once pressure is nolonger sensed by the sensing unit 14. Alternatively, the alarm may bedeactivated when the soft tissue pressure no longer exceeds thethreshold. To avoid unnecessary alarms, the system 10/58 may employ analgorithm that re-activates the alarm after a predetermined amount oftime after the alarm was deactivated. For example, the predeterminedamount of time may be based on the amount of time the soft tissuepressure exceeded the threshold. Alternatively, the algorithm mayfurther take into consideration patient data (age, gender,health/medical condition, etc.), the location of the sensing unit 14 onthe patient's body, and the soft tissue pressure (e.g., peak, trough,average, and median, etc.).

The systems 10 and 58 can also determine patient diagnosis and recommendtreatment based on certain categories of variables. A doctor, nurse,facility or researcher can use a predefined customized classificationsystem (for example, rated on a scale of 1-10) to specify a patientcategory for a given patient that is based on patient data such as age,gender, health/medical condition, etc. A Braden scale may also be usedinitially as an assessment tool for predicting the risk of pressureulcers based on the total of scores given in categories of sensoryperception, moisture, activity, mobility, nutrition, and friction orshear. Over time, the medical knowledge-based system 75 (FIG. 10) willpreferably accumulate information regarding specific patient and riskcharacteristics that can be used to refine the patient category assignedto a patient. In combination, the data obtained with the system 10/58can be used by an algorithm to assign a diagnosis category (e.g., on ascale of 1 to 10) to a patient based on a predefined customized categorythat reflects the amount of pressure and the amount of time at onelocation of the patient's body that has specific locationcharacteristics, which may also be rated on a scale of 1-10.

As a nonlimiting example of the above, X amount of pressure for 60minutes on the sacrum of a patient may be assigned a 5 rating as adiagnosis category. A treatment category can then be based on thediagnosis category as well as the patient category for the patient. Forexample, based on the diagnosis category (e.g., the amount of pressure,the amount of time for a specific location) and the patient category,the treatment category may be used to specify how long the patientshould not be on the particular part of the body, ranked on a scale of,for example, 1-10. For example, given a patient category 8 that has asacrum rating of 5, the system 10/58 may immediately prescribe atreatment category of 3 on a scale of 1-10.

FIGS. 15-28 represent preferred embodiments of graphic user interfacescreens that may be displayed on the tablet's display 26 for use by acaregiver to monitor patients using the systems 10 and 58, andparticularly the system 58 depicted in FIG. 10. In particular, BLEsignals broadcast from a sensor 30 of a sensing unit 14 to the Internetcloud 62 (FIG. 10) are encrypted to HIPAA standards and include a sensorID, battery status, pressure switch state, and signal strength alongwith potential additional data. As an example, data is sent from thesensing unit 14 via a configuration setting every 0.5 to every 5 minutesor every 1 to 5 minutes for preventative locations. In preferredembodiments, data can be achieved but not deleted from the system 10/58.All data changes are synched with the cloud 62 when online. When thesystem 10/58 is offline, data is stored and synched at the firstopportunity that the system 10/58 is back online.

As illustrated in FIG. 15, after a user directs a browser to the websitelogin page of the system 10/58, a screen 82 appears that includes aquestion mark icon 84. The question mark icon 84 preferably appears onall interface screens displayed to users of the system 10/58. A userenters a login into a login dialog box 86 and a password into a dialogpassword box 88, then clicks a sign in dialog button 90 to gain entryinto the software.

After a user successfully logs into the system, FIG. 16 illustrates awelcome screen 92 that includes an administration (“Admin”) tab 94, apatient information (“Patient Info”) tab 96 and a monitor (“Monitor”)tab 98. Clicking the administration tab 94 brings the user to anadministrative (“Admin”) screen illustrated in FIG. 17 that includesadditional links including a facilities module 100, a users module 102,a settings module 104, and a reports module 106.

FIG. 18 illustrates the facilities module 100 that can be accessedthrough the administrative screen of FIG. 17 to allow users to add,change and/or delete organizations and sub-organizations, includingdetails such as name, address, floor, and section descriptions. Onlycertain users such as super users with administrative rights arepreferably allowed to add, change, and/or delete certain data in thesystem 10/58.

FIG. 19 illustrates the users module 102 that can be accessed throughthe administrative screen of FIG. 17 to allow users to add, change and/or delete users including details such as name, unit/floor,designation, phone, email, username, and password.

FIG. 20 illustrates the settings module 104 that can be accessed throughthe administrative screen of FIG. 17 to allow users to add, changeand/or delete certain parameters associated with certain sensorsincluding an alarm threshold 108 (such as that discussed in reference toFIG. 10) and an alarm clear time 110. A set of alarm settings 112 areconfigurable including a sound option 114, a volume option 116, aduration option 118, and an interval option 120.

FIG. 21 illustrates the reports module 106 that can be accessed throughthe administrative screen of FIG. 17 to allow users to choose differentreports including an alarm report 122, a pressure ulcer (PU) statusreport 124, a usage report 126, and a history report 128.

FIG. 22 illustrates an example screen of the history report 128 thatincludes a listing of sensor descriptions 130 and a visual summary 132associated with each sensor 30 displaying alerts based on time andpressure data. A set of visual status alerts 134 includes a no pressurestatus 136, an overpressure status 138, a pressure threshold alarmstatus 140, a pressure alarm relieved status 142, a low battery status144, and a stopped sensor status 146.

FIG. 23 illustrates a patient screen that can be accessed through thewelcome screen 92 of FIG. 16 to allow users to add, change and deletepatients in the system 10/58. The patient screen includes detailedpatient information such as name, unit/room, ID#, gender, and date ofbirth.

If a user selects a particular patient after selecting the patient tab96, the user lands on the patient detail screen illustrated in FIG. 24,which includes additional data such as patient weight, diagnosis,mobility, bed type, Braden, PURS (Pressure Ulcer Risk Scale), existingPUs, and new PUs. If a user selects an existing or new PU, FIG. 25illustrates a PU status screen that includes dropdown menu options forspecific PU status, location, stage/category, date and time.

FIG. 26 illustrates the monitor user interface that can be accessedthrough the welcome screen 92 of FIG. 16 when the monitor tab 98 isselected. In particular, a visual indication of each sensor 30 and itslocation on the patient is illustrated on a human outline 148 in apatient sensor status window. The visual indication of each sensor 30comprises a label 154 with information that identifies the sensor 30. Asshown, each label 154 also incorporates an elapsed time progress bar,which may display elapsed time and warnings in the same manner asdescribed for the progress bars 52 discussed in reference to FIGS. 5Aand 5B. In particular, FIG. 26 indicates each label 154 as reflectingthe sensor status discussed in reference to FIG. 22, namely, color-codedvisual status alerts 134 that include a no pressure status 136, anoverpressure status 138, a pressure threshold alarm status 140, apressure alarm relieved status 142, a low battery status 144, and astopped sensor status 146. An alarm history window 150 lists a historyof past sensor alarms.

As illustrated in FIG. 27, a sensor detection window 152 is displayedwhen the tablet 13 is located near a sensor 30 and a button on thesensor 30 is depressed (not shown) to automatically detect the sensor30. As illustrated in FIG. 28, if a user selects a sensor label 154 inthe human outline 148, a sensor window 156 is displayed to allow theuser to enter additional information on the sensor 30 and alarmthresholds. The sensor 30 can be registered using QR Codes to associatethe particular sensor 30 with a patient and with part of that patient'sbody. For this purpose, the caregiver places the sensor 30 adjacent tothe tablet 13 or the smartphone 68, which includes an application toread the QR label. In particular, the caregiver can use the smartphone68 to take a picture of the QR label, which is read and processed by theapplication. The application then has a label with unique identificationof the sensor 30. The user then drags the label 154 to a specific partof the body illustrated in the human outline 148 that serves as avisualization of the patient. When the user is done dragging the label154 onto the part of the body of the patient, the user releases thebutton and the label 154 is associated with the part of the body wherethe label 154 is released.

Additional registration of the sensor 30 in the system 10/58 includesmeasuring the signal strength to detect the proximity of the sensor 30,a user pushing a button on the sensor 30 to initiate proximity detectionof the sensor 30 so the sensor 30 can be registered in the system 10/58,or a user pushing the button in a unique sequence over a predefinedperiod of time to initiate registration.

In addition to locating pressure sensing units 14 on a human body, it isforeseeable that the systems 10 and 58 may be used on other objectsdepending on the application. For example, it is also foreseeable that asensing unit 14 could be incorporated into a prosthetic worn by a personto monitor pressure between the prosthetic and the person's skincontacted by the prosthetic, or located on or in a surface that a personwill sit or lie on, such as wheelchairs, chairs, vehicle seats, bicycleseats, etc., or covers for such devices. Additionally, the sensing units14 may be located in furniture, clothing, sporting equipment, or anyother location where tracking pressure over a period of time isdesirable. For example, FIG. 7 represents the system 10 being used witha wheelchair 56 and having pressure sensing units 14 located on or in aseat of the wheelchair 56.

The pressure monitoring systems 10 and 58 could be combined with otherknown types of sensors and transducers in order to provide a morecomprehensive status of a patient. For example, the systems 10 and 58may be configured to sense the patient's heart rate and/or bloodpressure and transmit this information to the tablet 13 to be displayedwith the pressure information. Alternatively, the software applicationof the tablet 13 may be configured to communicate with existing heartrate and/or blood pressure monitoring devices and incorporate thisinformation into the display. In either case, the software applicationon the tablet 13 may be configured with preset limits for the patient'sheart rate and/or blood pressure in substantially the same manner asdescribed above relating to the pressure monitoring. As such, thesoftware application may display a warning if the patient's heart rateor blood pressure drops below or exceeds the preset limits.

While the invention has been described in terms of specific embodiments,it is apparent that other forms could be adopted by one skilled in theart. For example, the pressure monitoring systems 10 and 58 and itscomponents could differ in appearance and construction from theembodiment shown in the Figures, the functions of each component couldbe performed by components of different construction but capable of asimilar (though not necessarily equivalent) function, and variousmaterials and assembly, calibration and test procedures could be used inthe manufacturing and setup of the systems 10 and 58. Other optionsinclude the use of different packaging, timer and pressure measurementmodalities (including variable output pressure transducers), and the useof any number of pressure sensing units 14 and sensors 30, includingdifferent types of sensor technologies to measure a range of specificpressures. In addition, various different threshold pressure levelscould be used, though a pressure level of 30 mmHg is currentlyuniversally accepted as a critical threshold pressure level in thedevelopment of pressure ulcers.

The system can also be configured for use by home patients andwheelchair patients, as well as for placement in the shoes of ambulatorypatients to measure and warn against excess foot pressure-time. Thesystem can also be adapted for use in treating pre-existing wounds andto incorporate wound care dressings into the pressure sensing units 14,for example, by impregnating a dressing layer of a pressure sensing unit14 with topical antibiotics to aid in the treatment of bacterialinfected wounds. The system may additionally include temperature sensorsto detect if the skin is increasing the probability of a PU for alertingand time. Moisture sensors could detect if the skin is increasing theprobability of a PU for alerting and time as well.

A variable pressure transducer could assist in relating a patient'sweight and other health factors when configuring alerts and alarms. Thesystem could also detect if a patient was out of the bed or a seat ifall sensors are not reading any pressure. The system could furtherinclude skin capillary stimulation if the skin is increasing theprobability of a PU for alerting and time. The system could detectsoftness and hardness of various beds and seats using a pressure sensor.A bed pad or chair pad could be embedded with sensors and time alerting,along with artificial limbs. The system could employ predictiveanalytics based on age, multi-sensor information and other metrics. Careof patients could be socialized to family members can remotely monitorthe patients.

The system could further include a soil detection alert. Finally, abacterial burden value could be calculated to alert a high probabilityof a PU. Accordingly, it should be understood that the invention is notlimited to the specific embodiments illustrated in the Figures. Itshould also be understood that the phraseology and terminology employedabove are for the purpose of disclosing the illustrated embodiments, anddo not necessarily serve as limitations to the scope of the invention.Therefore, the scope of the invention is to be limited only by thefollowing claims.

1. A carrier comprising: a plurality of layers comprising at least afirst inner layer, at least a first interior layer, and at least a firstfoam layer embedded between the first inner layer and the first interiorlayer, the first inner layer and the first interior layer being formedof at least one dressing material; an aperture within the carrier anddefined by at least a first opening in the first foam layer; an adhesivestrip that releasably overlies the aperture, can be peeled back toexpose the aperture, and then reapplied over the aperture; and at leastan additional layer overlying the first inner layer, the first interiorlayer, the first foam layer, and the adhesive strip.
 2. The carrier ofclaim 1, wherein the aperture within the carrier is further defined byat least a second opening in the first interior layer.
 3. The carrier ofclaim 2, further comprising a second foam layer on the first interiorlayer such that the first interior layer is between the first and secondfoam layers, and the aperture is further defined by at least a thirdopening formed within the second foam layer.
 4. The carrier of claim 3,further comprising a second interior layer on the second foam layer suchthat the second foam layer is between the first and second interiorlayers and the second interior layer is between the second foam layerand the adhesive strip.
 5. The carrier of claim 4, wherein the apertureis further defined by at least a fourth opening formed within the secondinterior layer.
 6. The carrier of claim 4, further comprising a thirdinterior layer between the first inner layer and the first foam layer.7. The carrier of claim 6, wherein the aperture is further defined by atleast a fourth opening formed within the third interior layer.
 8. Thecarrier of claim 6, wherein the first inner layer, the third interiorlayer, and the first foam layer are the same size.
 9. The carrier ofclaim 8, wherein the first interior layer, the second foam layer, andthe second interior layer are the same size.
 10. The carrier of claim 9,wherein the first interior layer, the second foam layer, and the secondinterior layer are smaller than the first inner layer, the thirdinterior layer, and the first foam layer.
 11. The carrier of claim 1,further comprising a second interior layer between the first inner layerand the first foam layer.
 12. The carrier of claim 11, wherein theaperture is further defined by at least a second opening formed withinthe second interior layer.
 13. The carrier of claim 1, wherein the innerlayer is a lowermost layer of the carrier for directly facing apatient's skin, is a non-adhesive foam or absorbent material, and doesnot have an opening therein.
 14. The carrier of claim 13, wherein theinner layer has an adhesive covering along a border thereof adapted toadhere the carrier to skin.
 15. The carrier of claim 1, wherein theaperture is centrally located within the carrier.
 16. The carrier ofclaim 1, wherein the first inner layer and the first foam layer define around periphery of the carrier.
 17. The carrier of claim 1, wherein thefirst inner layer and the first foam layer define an oval periphery ofthe carrier.
 18. The carrier of claim 1, wherein the dressing materialis a foam, hydrocolloid, or alginate self-adherent dressing.
 19. Apressure sensing unit comprising the carrier of claim 1 and a sensorwithin the aperture, the sensor comprising at least a first pressuretransducer, the sensor wirelessly transmitting an electrical outputsignal generated by the transducer, and the adhesive strip releasablyoverlying the aperture to secure the sensor within the aperture, can bepeeled back to expose the aperture and the sensor, and then reappliedover the aperture to secure the sensor within the aperture.
 20. Thepressure sensing unit of claim 19, wherein the sensor comprises aprinted circuit board and the first transducer is located on the printedcircuit board.
 21. The pressure sensing unit of claim 20, wherein thesensor comprises a vibration device located on the printed circuit boardand adapted to generate a vibration alarm.
 22. A pressure sensing unitcomprising the carrier of claim 7 and a sensor within the aperture, thesensor comprising at least a first pressure transducer, the sensorwirelessly transmitting an electrical output signal generated by thetransducer, and the adhesive strip releasably overlying the aperture tosecure the sensor within the aperture, can be peeled back to expose theaperture and the sensor, and then reapplied over the aperture to securethe sensor within the aperture.
 23. The pressure sensing unit of claim22, wherein the sensor comprises a printed circuit board and the firsttransducer is located on the printed circuit board.
 24. The pressuresensing unit of claim 23, wherein the sensor comprises a vibrationdevice located on the printed circuit board and adapted to generate avibration alarm.